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Preparation, X‐Ray Diffraction Pattern, and Solubility Product of Manganese(III) Phosphate Hydrate
Author(s) -
Boyle F. W.,
Lindsay W. L.
Publication year - 1985
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1985.03615995004900030045x
Subject(s) - manganese , hydrate , chemistry , inorganic chemistry , solubility , phosphate , powder diffraction , crystallography , organic chemistry
No characterization of MnPO 4 ·1.5H 2 O (manganese [III] phosphate hydrate), other than x‐ray diffraction patterns, has been reported even though this compound has been recognized as a reaction product of manganese‐ and phosphorus‐containing solutions. Evaluation of the chemical and physical properties of MnPO 4 ·1.5H 2 O is necessary prior to the study of this solid as a possible reaction product in soils. This mineral was prepared by reacting H 3 PO 4 (orthophosphoric acid) with each of the following: MnCO 3 (c) (manganese [II] carbonate), MnOOH(c) (manganese [III] hydroxyoxide), and MnO(c) (manganese[II] monoxide). The reaction pathways were found to involve O 2 (g) as the electron acceptor. An intermediate compound, MnOOH(c), was isolated during the reaction by filtering the suspension following the cessation of CO 2 (g) evolution. X‐ray diffraction patterns were obtained and were matched with previously reported patterns. The refractive index was found to be approximately 1.73. The density was measured pycnometrically and was determined as being 2.5703 ± 0.0014 Mg m −3 . The equilibrium constant ( K °) for the following reaction: MnPO 4 ·1.5H 2 O(c) = Mn 2+ + PO 3− 4 + 1.5H 2 O was found to be 10 −34.82 with σ = 0.46.